SOIL PHYSICAL QUALITY AFTER NITROGEN FERTILIZERS USE IN IRRIGATED PASTURE OF TIFTON 85

Tifton 85 (Cynodon sp.) is a forage crop widely used for the voluminous production, but it has also the potential to promote preservation or improvement in soil structural quality, when well managed. The aim of this work was to evaluate the soil physical quality in a rotational grazing area of Tifton 85 under irrigation in Prudente de Morais, MG, Brazil, due to the application of mineral and organic nitrogen fertilizers. The treatments included different forms of N supply: 400 kg ha -1 of urea; 400 kg ha-1 of bovine manure; 400 kg ha-1 of urea and manure, in proportion 1:1 and the control, without nitrogen fertilization. The following soil physical quality indicators were determined in the layers 0.0-0.05 m and 0.05-0.10 m after two years of N application: water retention curve, total porosity, macroporosity, microporosity, soil bulk density, available water capacity, bulk soil air capacity, soil matrix air capacity and relative water capacity. There were differences among the treatments, in both layers. In general, the treatments using bovine manure promoted greater water storage and availability, which was related to the increase of the microporosity, due to the organic matter effect. However, these same treatments presented a relative compaction, which was associated to the maintenance of higher soil moistures. It was concluded that, even under the effects of intensive grazing, there was generally adequate soil physical quality, but a special attention is recommended to the soil susceptibility to compaction

ESTRUTURA DE SOLOS EM MANEJO CONSERVACIONISTA: DIAGNÓSTICO VISUAL, LABORATORIAL, CARACTERIZAÇÃO E INTER-RELAÇÕES

A qualidade estrutural dos solos vem sendo avaliada por indicadores físicos obtidos em condições laboratoriais, que embora sejam os mais aceitos, têm obtenção onerosa, além do tempo necessário para transporte das amostras e demora na apresentação dos resultados. A análise visual da estrutura obtida em campo vem sendo apontada como opção viável para o diagnóstico da qualidade física do solo, constituindo uma importante ferramenta para identificar ou monitorar práticas de manejo sustentáveis. Assim, este trabalho teve por objetivo analisar a relação entre análise visual e laboratorial da estrutura objetivando diagnóstico da qualidade física de diferentes solos. Utilizou-se delineamento experimental inteiramente casualizado em esquema fatorial duplo, sendo os fatores as classes de solos (LVd, CXbd e NXd), avaliadas em diferentes profundidades (amontoa; 0,05-0,15 m; 0,25-0,35 m; e 0,45-0,55 m ), em triplicata. A avaliação se apoiou na aparência visual da estrutura dos solos após 5 anos da implantação de um sistema de manejo conservacionista, sendo avaliadas a resistência e outros atributos das unidades estruturais dos solos, categorizados por 5 Scores visuais (Ev) utilizados na classificação da qualidade da estrutura, variando de Ev =1 (melhor qualidade) a Ev =5 (pior qualidade). Nas profundidades de 0,25-0,35 m e 0,45-0,55 m, o LVd apresentou Score visual menor quando comparado ao NXd e CXbd, indicando sua melhor condição estrutural nestas profundidades. A análise de componentes principais  demonstrou que a quantificação dos atributos densidade do solo, microporosidade, teor de silte e poros da classe de diâmetro < 0,6 µm contribuíram para justificar o aumento do Ev.

Accuracy and calibration of capacitance probe in a Rhodic Ferralsol planted with coffee

O objetivo deste trabalho foi determinar a acurácia da sonda de multisensores de capacitância "Delta‑T Profile probe PR2/6", na avaliação do conteúdo de água do solo com uso de calibrações padrão do fabricante, realizar a calibração para condições específicas de locais e profundidades de amostragem do solo e obter coeficientes de calibração para medições acuradas em tempo real. Em janeiro de 2010, foram coletadas amostras de solo com estrutura preservada a diferentes profundidades, nas linhas de plantio do cafeeiro e nas entrelinhas. As análises foram realizadas em laboratório, com o sensor ML2x Theta probe. Após a obtenção das leituras do sensor, o teor de água foi determinado por meio do método gravimétrico. Foram utilizadas amostras de Latossolo Vermelho distrófico muito argiloso. As calibrações padrão do fabricante (mineral e orgânica) não não se mostraram adequadas para emprego nas condições de manejo (locais e profundidades de amostragem) avaliadas. Na impossibilidade de averiguar a acurácia obtida pelo método recomendado pelo fabricante, o uso de ajustes de regressão linear ou da ferramenta Solver mostrou-se útil no processo de calibração. São necessárias apenas duasequações de calibração para avaliação do teor de água das situações contrastantes de manejo.The objective of this work was to determine the accuracy of the Delta‑T Profile PR2/6 multisensor capacitance probe in the evaluation of soil moisture content using default calibration equations from the manufacturer, to perform the calibration for specific soil sampling locations and depths, and to obtain calibration coefficients for accurate measurements in real time. In January 2010, samples were taken with structure preserved at varying soil depths, at the planting rows or in between the rows. The analyses were done in laboratory using the ML2x Theta probe sensor. After obtaining the outputs from the sensor, water content was determined by the gravimetric method. Samples were taken from a clayed Rhodic Ferralsol. The manufacturer calibration standards (mineral and organic) were not suitable for the evaluated management (sampling location and depths) conditions. Given the impossibility to verify the accuracy obtained by the method indicated bythe manufacturer, the use of linear regression adjustments or of the Solver tool was useful in the calibrationprocess. Only two calibration equations are necessary to evaluate the contrasting management situations

Changes in soil profile hydraulic properties and porosity as affected by deep tillage soil preparation and Brachiaria grass intercropping in a recent coffee plantation on a naturally dense Inceptisol

Soil management operations change soil porosity, affecting water infiltration, redistribution, storage, availability, and uptake by plants. Assessing how soil management may affect pore size distribution and hydraulic conductivity is thus highly relevant for rainfed agriculture coping with water shortage. The aim of this study was to assess the effectiveness of tillage treatments, designed to deepen coffee plants root system, on improving structure and physical-hydric attributes of an Inceptisol with a shallow solum. The study was conducted in an experimental area in the municipality of Nazareno, Minas Gerais State, Brazil. Soil samples were collected 18 months after coffee plantation, at different depths (0, 0.25, 0.35, 0.45, 0.55, 0.66, and 0.75 m) and they were used to determine pore-size distribution, saturated and unsaturated hydraulic conductivity. Samples were also collected in surface crusts or in the 0−0.005 m soil layer for detailed grain size analysis. Field water infiltration was measured at different water tensions. Coffee seedlings were planted in rows furrowed to depths depending on tillage treatment: 0.4 m depth, made by a furrow ridger (FP40); 0.6 m depth, made by a subsoiler coupled to a soil preparer mixing the soil to a depth of 0.6 m (FP60); 0.8 m depth, made by a subsoiler and, after mixing the soil to a depth of 0.6 m, by the soil preparer (FP80). The soil between the planting rows was covered by Brachiaria-grass. Soil sampling and field tests were performed in the coffee plants row mechanically treated, in the Brachiaria-grassed inter-row (IR) lane and in a nearby area under natural vegetation (NC). Treatments effects, either mechanical in the coffee rows (FP40, FP 60 and FP80), or biological in the inter-row lane (IR) were compared to reference (NC), representing soil conditions prior to coffee plantation. The FP60 and FP80 treatments improved water infiltration, storage and hydraulic conductivity in the planting rows to a depth of 0.5 m. A more favorable pore size distribution was obtained following these treatments, which improved the soil physical environment. Conversely, furrowing promoted compaction at each implement working depth due to the pressure applied by the rods in the subsurface soil layers, combined with subsoil moisture condition at the time of operations. Root activity of intercropped Brachiaria-grass (IR) improved soil structure, expressed by a favorable pore-size distribution and a faster hydraulic conductivity in the inter-row lane. Similar effects were obtained with FP 60 and FP80 for the coffee rows, where deep furrowing during soil preparation reduced the natural density of the Inceptisol. Therefore, the management strategies tested allowed root deepening and access to soil moisture stored in deeper layers.To Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for granting the scholarship and to the funding agencies Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG), CNPq, and Consórcio Brasileiro de Pesquisa e Desenvolvimento do Café - (CBP&D/Café) of Empresa Brasileira de Pesquisa Agropecuária - Unidade Café (Embrapa Café). To Universidade Federal de Lavras (UFLA) and Departamento de Ciência do Solo (DCS) for the provided support. To Frade farm for allowing and aiding in the installation of the experiment and to IF Goiano for support of our research.info:eu-repo/semantics/publishedVersio

Available soil water upper limit by modeling and direct determination in a greenhouse

Pot capacity (PC) is a direct method of determining field capacity (FC) for experiments with plantings in pots. The objective of this study was to evaluate different laboratory methods to determine field capacity and compare them with the pot capacity method. The experimental design was completely randomized (CRD), with nine treatments (methods of obtaining FC) and four replications, totaling 36 experimental plots. The mean values of moisture contents in the FC of the nine methods were compared, being eight empirically obtained and one directly in the greenhouse, defined as a control treatment (PC). The relative accuracy (RA) for all treatments was determined in relation to the control treatment. The estimation of the upper limit of available water in the soil varies depending on the method, and a decreasing order of moisture levels can be observed at FC: FC-Lab4pts &gt; FC-Labip &gt; FC-Lab8pts &gt; PC &gt; FC-Lab6pts &gt; FC-6KPa &gt; FC-LabSWRC &gt; FC-10KPa &gt; FC-33KPa. The treatment FC-Lab6pts has the relative accuracy closest to 100% and can be a practical alternative to PC. The use of 4, 6, 8 or 10 points for modeling the SWRC does not interfere with the quality of the FC estimated by the Dexter inflection point method, which is much more efficient for experiments of this nature. The use of potentials -10 kPa and -33 kPa is not adequate to estimate FC in tests with pots in a greenhouse

Soil Management and Water-Use Efficiency in Brazilian Coffee Crops

Brazil is a world leader in coffee production. However, currently, it coexists with recurrent and severe droughts, accompanied by intense heat, strong insolation and low relative humidity. As the cultivation is carried out primarily in the rainy season, these world climate variations have affected crops yields and fruits quality, requiring innovative actions that promote efficient use of water stored in the soil. Among several soil management practices that promote a more rational use of water, deep tillage combined with liming, gypsum and fertilizer amendments lead to an increase in effective depth of coffee roots, therefore reducing water stress. Moreover, intercropping with Urochloa sp. is highly efficient in enhancing soil structure, water infiltration and plant available water capacity. Additionally, other innovative techniques and practices are also introduced in this chapter

Estrutura de solos em manejo conservacionista: Diagnóstico visual, laboratorial, caracterização e inter-relações

The visual analysis of soil structure can be a useful and practical tool for monitoring soil physical condition in conservation management systems. Thus, the objective of this work was to analyze the relationship between visual and laboratorial diagnosis of soil structure, in a conservation management system. We utilized completely randomized experimental design in a factorial double was used, the factors being soil classes (Haplic Cambisol, Red Latosol and Haplic Nitosol), evaluated at different depths (pille [-0.05-0.15 m]; 0.05-0.15 m; 0.25-0.35 m and 0.45-0.55 m) in triplicate. The evaluation was based on the visual appearance of the structure of the soil after five years of implementation of a management system considered conservationist, being analyzed resistance, consistency, porosity and presence of roots in the structural units of the soils, categorized by five visual scores (Ev) used in quality grading structure, ranging from Ev = 1 (best quality) at Ev = 5 (worst quality). In order to evaluate the physical attributes of the soil (macroporosity, microporosity, pore distribution by size and soil density), undisturbed samples were collected and submitted to matrix potentials -2, -4, -6, -10 kPa in the suction units, and -33, -100, -500, -1500 kPa in the Richards chamber. The aggregation was evaluated by the geometric mean diameter. We observed in the depths of 0.25-0.35 and 0.45-0.55 m, the Latosol presented visual score lower when compared to Nitosol and Cambisol, indicating its better structural condition in these depths, comparative form to other soils analyzed. The increase of the visual scores is related to the loss of the structural porosity (inter aggregates) and increase of the textural porosity (intraaggregates). The principal component analysis demonstrated that quantification of the attributes density, microporosity, silt content and the pore diameter class < 0.6 μm helped to justify the increase in Ev.A análise visual da estrutura do solo pode ser uma ferramenta útil e prática no monitoramento da condição física do solo em sistemas de manejo conservacionista. Assim, o objetivo deste trabalho foi analisar a relação entre o diagnóstico visual e laboratorial da estrutura do solo, em sistema de manejo conservacionista. Utilizou-se delineamento experimental inteiramente casualizado em esquema fatorial duplo, sendo os fatores as classes de solos (CAMBISSOLO HÁPLICO, LATOSSOLO VERMELHO e NITOSSOLO HÁPLICO), avaliadas em diferentes profundidades (amontoa [-0,05-0,15 m]; 0,05-0,15 m; 0,25-0,35 m; e 0,45-0,55 m), em triplicata. A avaliação se apoiou na aparência visual da estrutura dos solos após 5 anos da implantação de um sistema de manejo conservacionista, sendo avaliadas a resistência, consistência, porosidade e presença de raízes nas unidades estruturais dos solos, categorizados, segundo a carta padrão, por 5 escores visuais (Ev) utilizados na classificação da qualidade da estrutura, variando de Ev =1 (melhor qualidade) a Ev =5 (pior qualidade). Os atributos físicos do solo (macroporosidade, microporosidade, distribuição de poros por tamanho e densidade do solo), foram determinados em amostras indeformadas submetidas aos potenciais matriciais de -2, -4, -6, -10 kPa nas unidades de sucção, e -33, -100, -500, -1500 kPa nas câmaras de Richards. A agregação foi avaliada pelo diâmetro médio geométrico. Nas profundidades de 0,25-0,35 m e 0,45-0,55 m, o Latossolo apresentou Ev menor quando comparado ao Nitossolo e Cambissolo, indicando sua melhor condição estrutural nestas profundidades. O aumento dos Ev está relacionado à perda da porosidade estrutural (interagregados) e incremento da porosidade textural (intraagregados). A análise de componentes principais demonstrou que a quantificação dos atributos densidade do solo, microporosidade, teor de silte e poros da classe de diâmetro < 0,6 μm contribuíram para justificar o aumento do Ev